title: Surface-enhanced Raman spectral measurements of 5-fluorouracil in saliva.
abstract: The ability of surface-enhanced Raman spectroscopy (SERS) to measure 5-fluorouracil (5-FU) in saliva is presented. The approach is based on the capacity of Raman spectroscopy to provide a unique spectral signature for virtually every chemical, and the ability of SERS to provide microg/mL sensitivity. A simple sampling method, that employed 1-mm glass capillaries filled with silver-doped sol-gels, was developed to isolate 5-FU from potential interfering chemical components of saliva and simultaneously provide SERSactivity. The method involved treating a 1 mL saliva sample with 1 mL of acetic acid, drawing 10 microL of sample into a SERS-active capillary by syringe, and then measuring the SER spectrum. Quality SER spectra were obtained for samples containing as little as 2 microg of 5-FU in 1 mL saliva. The entire process, the acid pretreatment, extraction and spectral measurement, took less than 5 minutes. The SERS of 5-fluorouridine and 5-fluoro-2'-deoxyuridine, two major metabolites of 5-FU, were also measured and shown to have unique spectral peaks. These measurements suggest that disposable SERS-active capillaries could be used to measure 5-FU and metabolite concentrations in chemotherapy patient saliva, thereby providing metabolic data that would allow regulating dosage. Tentative vibrational mode assignments for 5-FU and its metabolites are also given.
authors.affiliation: Real-Time Analyzers, Inc., Middletown, CT 06457, USA. stu@rta.biz
authors.forename: Stuart
authors.initials: S
authors.lastname: Farquharson
authors.forename: Alan
authors.initials: A
authors.lastname: Gift
authors.forename: Chetan
authors.initials: C
authors.lastname: Shende
authors.forename: Frank
authors.initials: F
authors.lastname: Inscore
authors.forename: Beth
authors.initials: B
authors.lastname: Ordway
authors.forename: Carl
authors.initials: C
authors.lastname: Farquharson
authors.forename: John
authors.initials: J
authors.lastname: Murren
mesh_terms: D005472:Fluorouracil / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D015394:Molecular Structure; D012463:Saliva / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D005472:Fluorouracil